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[Closed] Bars for a DH bike

 spw3
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[#4023788]

How light can you go?

I'm going to get some flat(ter) bars for my DH bike this year, last year the front kept sliding out.

Some of the flat bars are pretty light, so how low can you go? I have started to wonder if my DH bike really needs to be quite so over built in certain areas such as the stem, bars, cranks.

(The biggest drop I have or ever will do are the A-line rock drop and the big GLC drop.)


 
Posted : 30/05/2012 10:41 pm
 GW
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It's not just about strength when landing drops.
How tall are you?
How heavy?
How/where do you ride?
And what do you ride? (Inc set-up?)
All matter!


 
Posted : 30/05/2012 10:45 pm
 spw3
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Height I doubt matters. But weight: 10stone, I'll be riding it in the Alps, it's a big hit with 888s.


 
Posted : 30/05/2012 10:56 pm
 GW
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Of course height matters


 
Posted : 30/05/2012 10:58 pm
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spw3

How light can you go?

Probably not a place I'd look to go saving too much weight from. The difference between a very light dh bar ( easton havoc carbon) and something that's not super light (renthal fatbars) is about 100 grams.

That's not to say the Eastons aren't strong, but they don't represent a massive weight saving.


 
Posted : 30/05/2012 11:04 pm
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Interesting GW. Why does height matter concerning bar strength? What difference would it make if I was 5 ft and 15 stone or 6ft and 15 stone to how strong I would need my bars. I would say it's more down to how much abuse you put your bike through and how much you value your neck.


 
Posted : 30/05/2012 11:07 pm
 spw3
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Yes I imagine the weight loss would not be great but I'm idly interested, in part bc I wonder how many bike components are needlessly overbuilt because they are intended for DH use.

GW - how does my height affect matters?


 
Posted : 30/05/2012 11:08 pm
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spw3

I'm idly interested, in part bc I wonder how many bike components are needlessly overbuilt because they are intended for DH use.

One mans needlessly overbuilt is another mans flexy p.o.s. I guess you could make the case that a lot of cheaper dh componentry is needlessly overbuilt to make it as comparatively strong as something expensive, light and strong....but then that overbuiltness is still serving some sort of purpose.

Again, really depends on who you are and what you do. Fabien Barel ran xtr cranks on his dh race bike. Most people run far heavier cranks but will never subject them to a fraction of the abuse he can. But then most people don't have free xtr cranks.


 
Posted : 30/05/2012 11:22 pm
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GW ๐Ÿ˜†
[img] [/img]


 
Posted : 30/05/2012 11:23 pm
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I'm guessing GW meant bar height relative to rider height.


 
Posted : 30/05/2012 11:24 pm
 spw3
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Well I'm pretty much decided that I need to get my weight down over the front wheel a bit more. Moving the shock position -which steepened the head angle - certainly helped. But I still don't buy that my height makes any difference to how light the bars can be.


 
Posted : 30/05/2012 11:32 pm
 GW
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Yes, mf it does matter.

I didn't think it was such a challenging question, OP clearly doesn't think the same.


 
Posted : 30/05/2012 11:36 pm
 spw3
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GW - honest question though,what's your thinking? Leverage?


 
Posted : 30/05/2012 11:38 pm
 GW
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google image 'Blood out a stone'


 
Posted : 30/05/2012 11:47 pm
 spw3
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Unnecessary.


 
Posted : 30/05/2012 11:54 pm
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Generally the front ends of bikes don't get taller with increasing rider height and frame size, the stack height, head tube length and axle to crown length stay the same.....thus taller riders either need to run shed loads of spacers or run higher rise bars....unless that is you want to give yourself back ache or wrist ache when in an attack position. Running loads of spacers places more stress on the steerer, making it more likely to break and also looking crap....whilst high risers can be flexier than lower rise bars. Take your pick.

GW was right. In fact I'm about to go to some higher rise bars as mine are two low and I cut my steerer too short. I'm running 740mm Syntace Vector carbons with 12 degree backsweep and a 10mm rise. The back sweep is wonderful and I'm loathe to get ride of them as I can't find anything similar with another 15-20mm rise.


 
Posted : 31/05/2012 1:24 am
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[url= http://ridegravity.com/products/gravity-777-handlebars/ ]Gravity 777 @ 319g [/url] on my Voltage FR last season.. I'm considering running [url= http://ridegravity.com/products/gravity-light-csi/ ]Gravity Light CSI carbon @ 240g[/url] on my bike this year. For no other reason that I like carbon stuff ๐Ÿ˜‰
The CSI's have been good to me on my 150mm trail bike, so why not stick them on my 36 float/40 shod park bike?!

I'm:
How tall are you? 183cm
How heavy? 11st
How/where do you ride? a little heavy on the bars/Whistler
And what do you ride? (Inc set-up?) Voltage FR


 
Posted : 31/05/2012 2:38 am
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all missing the key thing here chaps.

you WILL bin it at some point on your DH bike if you are having the appropriate amount of fun time!

stronger/heavier bars and you'll pick your bike up, bash your brake levers straight, and carry on.

xc/lighter/carbon bars and it's race/ride/day/holiday over.

why risk it?


 
Posted : 31/05/2012 7:53 am
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The Havoc carbon bars are lightweight compared to alu bars, but not compared to other carbon bars.

A good lightweight alu DH bar is 315g ish (Eg Easton Havoc alu)
Havoc carbon 235g (750mm)
Haven carbon (Easton's 710mm 'all mountain' bar) 170g vs 270 for the alu ones

Take from that what you will. The fact that the Havoc carbons are significantly heavier than the Havens suggests to me that the Havoc bars are pretty overbuilt and will be fine. I'd use them on my DH bike if I was rich enough.


 
Posted : 31/05/2012 8:25 am
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Searching for lightweight bars to go on a Big Hit LOL. Quality!


 
Posted : 31/05/2012 8:33 am
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It isn't just the rise that your height affects - why on earth would someone 5' tall with a 4'11" arm span want the same width bars as someone 6' tall with a 6'2" arm span? And if you're running wider bars (and are heavier and stronger) you'll need them to be stiffer to exhibit the same degree of flex when riding. I'd get the Havoc Carbons if they're wide enough and you can afford them - loving the Haven Carbon on my LTHT.


 
Posted : 31/05/2012 8:54 am
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I was also going to say you will be more likely to bin it quite hard and thus need a bar that can take that abuse.

The reasons I see why DH stuff is built tougher:

More/harder crashes
Faster runs over larger obstacles = higher loads + needs to be stiffer to reduce deflection
most use going down rocky descents = high fatigue risks
Wider = needing to cope with higher bending forces

Also weight is not really so much of an issue so it's okay and 100g goes a long way to making a bar stronger. Your bars and stem are not places to scrimp on for the sake of a few grams.

I was quite disappointed that my Havoc carbons are 235g as it is a big hike over the havens 170g. The havens felt very (and almost wrong!) light but the havocs have a good heft to them. But they are reassuringly heavy. I don't use them for downhill but I wanted wider bars than the havens and I wanted something strong that I can trust.

PS a taller rider is probably more likely to put more loading on the bars as there is only so much extra height you can put on the front of bike with spacers, riser stems, bars etc. In the same way for shorter riders the front of a bike is sometimes too high due to long travel fork. And then add that high rise bars need to be built stronger due to the shape.


 
Posted : 31/05/2012 9:01 am
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Looking at the information that came with my Havoc carbon bars.....Easton alu bars are warrantied for 5 years. The carbon ones have a lifetime warranty.

That's to say nothing of what a crash would do to either of them, but I think the carbon warranty is fairly reassuring and suggests it overbuilt?


 
Posted : 31/05/2012 12:13 pm
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So Josh Bryceland NEEDS much stronger bars than Sam Hill because he's 4" taller? ๐Ÿ™„


 
Posted : 31/05/2012 12:20 pm
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The older Easton carbon DH bars did utterly shite in some tests performed in Germany. Wouldn't touch them with a 10 foot barge pole until I've seen their stuff pas dh3 vr 2004 standards.


 
Posted : 31/05/2012 10:43 pm
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Buy the ones you like the look of. You're unlikely to have any problems with any appropriate, quality bar.

bwaarp - Member

dh3 vr 2004 standards.

That's one of those ones Syntace bang on about and nobody else has heard of isn't it? Nothing quite like making up your own standard...


 
Posted : 31/05/2012 10:50 pm
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I'd read a report somewhere where a bikemag did a stress test on various bars. I'll try to find it for you.

The Eastons didn't have a habit of breaking after a lot of stress cycles, but instead broke over a wide distribution of fatigue range. Suggesting that there was some poor manufacturing going on.

Generally I'd buy the strongest bar for a given weight as it's something that is stopping my face from planting the ground....over the looks.

It would be really nice if some company/magazine could do some borderline scientific tests for every product that is released, eastons may have picked up since that test....or it could have been a bad batch.... it would help give the consumer more information.


 
Posted : 31/05/2012 11:12 pm